1. Field of the Invention
This invention relates generally to an improved antenna for a motor vehicle and to a method of constructing the antenna.
2. Description of the Prior Art
The two forms of motor vehicle antennas that are most commonly used today are the mast antenna and the windshield antenna. The mast antenna comprises a rod conductor projecting outwardly from the motor vehicle body. In such an exposed location, the mast antenna is subject to deterioration by the weather elements, it is prone to damage from striking against external objects, and it is in a location easily accessible to vandals. In addition, the mast antenna is thought by some to detract from the aesthetic appearance of the motor vehicle. Of course, the mast antenna can be made to automatically retract within the motor vehicle body, but such an auxiliary powered arrangement contributes extra cost to the antenna.
In the windshield antenna, one or more very thin conductors are embedded within the windshield of the vehicle. Consequently, the conductors of the windshield antenna are, to a degree, shielded from the weather, damage from striking against external objects, and vandalism. The windshield antenna conducters are thin, typically 30 to 32 gauge. Because the conductors are so thin, they are still susceptible to cracking or breaking, and are not particularly useful as transmission antennas, due to their limited power handling capability. Further, the windshield antenna is somewhat susceptible to various forms of FM distortion, particularly "station swapping", and it is somewhat sensitive to changes in the direction of vehicle travel. Noise may also be generated in the windshield antenna by various accessories of the motor vehicle, such as by windshield wipers. The conductors of the windshield antenna also inevitably add to the cost of replacing a damaged vehicle windshield.
Antennas have also been incorporated into the dashboard of the motor vehicle. Since the dashboard is an integral part of the motor vehicle, to be economically feasible, this type of antenna must be initially ordered with the purchase of the motor vehicle, and is expensive and impractical to replace or repair.
Antennas have also been combined with a variety of motor vehicle accessory parts. These accessory parts include such items as molding, trim, grills, wheel covers, sun visors, side view mirrors, and insect guards for radiators. Such insect guard/deflector for the radiator is of an open mesh structure wherein the mesh itself forms the antenna conductors. In such structure, the conductor members for the antenna are exposed to the elements and, therefore, are susceptible to damage. The prior art insect guard/deflectors protect only the area immediately behind the guard. They do not deflect the air current away from the area, but only act as bug screens.
In general, the prior art antennas that are combined with automobile accessories provide for only one antenna. If two antennas are needed, it is necessary to install two separate units.
The incresed popularity of citizen band radios has created an increased demand for add-on antennas suitable for both reception and transmission. Typically, the standard automobile radio antenna cannot be also used as an antenna for a citizen's band radio unless a switching mechanism is mounted between the antenna and the two radios to enable only one unit at a time to use the antenna. By far, the most popular add-on antenna has been the mast antenna. The mast antenna is often mounted on the roof of the motor vehicle. The mounting base is often magnetic, so that the antenna can easily be removed. It is often necessary or desirable for a roof antenna to be removable because the combined height of the motor vehicle and the antenna may be higher than an overhead obstruction such as a parking ramp ceiling or a garage door. In such cases, the antenna would be damaged if it was not removed before the motor vehicle passed under the obstruction.
It would be advantageous if, when adding an additional antenna to the motor vehicle, the antenna could also provide another function for the motor vehicle, as for example, an air current deflector. An air current deflector shield accessory is normally mounted to the motor vehicle in one of three places. If attached to the front edge of the hood of the motor vehicle, the air current deflector shield deflects the air current so that insects would be carried by the deflected air current over and above the motor vehicle. Air current deflector shields are also often attached to the back edge of the roof of a station wagon. In this position, the air current deflector shield helps to keep the rear window of the station wagon clean. A third position where air current deflector shields are often attached is to the leading edge of the roof of a motor vehicle. In that position, the air streams flowing over the roof of the motor vehicle are deflected away from the leading blunt surface of a trailing vehicle. Such a shield would of course be structurally more substantial than the shield attached to the front edge of the hood or trailing edge of the roof of a station wagon.
To date, there has been no known structures which combine an antenna with an air current deflector shield having a solid surface.